When the public school office of the 6th district of Paris summoned me to a meeting late last year, the tone of urgency in the letter sent me running down the block, into the 19th century courtyard of the town hall and up the narrow stairs to the top floor.

"What does your son eat for lunch?" the woman asked after I ran in breathless. I had no idea what to say. When my son started nursery school last September at the age of 3, I had registered him for the school lunch program. But when he failed to appear in the lunchroom after that, city officials quickly took notice. My explanation — that I thought he should take a break and eat lunch at home in the middle of the day — was apparently not sufficient. This was personal.

"The food is very good, Madame. The meat is 100% French," the official said, picking up a brochure from her desk. I knew this brochure well, having e-mailed it to friends in the U.S. last year as a this-could-only-happen-in-France conversation piece. It lists in great detail the lunch menu for each school day over a two-month period. On Mondays, the menus are also posted on the wall outside every school in the country. The variety on the menus is astonishing: no single meal is repeated over the 32 school days in the period, and every meal includes an hors d'oeuvre, salad, main course, cheese plate and dessert.

There is more: the final column in the brochure carries the title "Suggestions for the evening." That, too, changes daily. If your child has eaten turkey, ratatouille and a raspberry-filled crepe for lunch, the city of Paris suggests pasta, green beans and a fruit salad for dinner.

I finally saw the system in action earlier this month. Caught short by a sick nanny, my son, who was accustomed to eating leftovers from the refrigerator, sat in silence with his 25 classmates at tables in the nursery-school cafeteria, while city workers served a leisurely, five-course meal. One day, when I arrived to collect him, a server whispered for me to wait until the dessert course was over. Out in the hall, one of the staff shouted for "total quiet" to a crowd of 4-year-olds awaiting the next lunch seating. "I will now read you today's menu," he told them. "First, you will begin with a salad."

Americans struggling with obesity epidemics have for years wondered how the so-called French paradox works: How does a nation that ingests huge quantities of butter, beef and cakes keep trim and have such long lives? It could be the red wine, as some believe. But another reason has to be this: in a country where con artists and adulterers are tolerated, the laws governing meals are sacrosanct and are drummed into children before they can even hold a knife. The French don't need their First Lady to plant a vegetable garden at the Élysée Palace to encourage good eating habits. They already know the rules: sit down and take your time, because food is serious business.

In his new book Food Rules, Michael Pollan states in rule No. 58: "Do all your eating at a table." French children quickly learn that they won't be fed anywhere else. Snack and soda machines are banned from school buildings in France — a battle that is now raging across the U.S. And France's lunch programs are well funded. While the country is cutting public programs and civil-servant jobs to try to slash a debt of about $2.1 trillion, no one has dared to mention touching the money spent on school lunches.

Public schools in France are overcrowded, rigid and hierarchical. And parents, who are never addressed by their first names, are strongly discouraged from entering school buildings, let alone the classrooms. I cannot tell you what my child learns, paints or builds on any given school day. But I do know that on Feb. 4, he ate hake in Basque sauce, mashed pumpkin, cracked rice, Edam cheese and organic fruits for lunch. That meant stuffed marrows and apples for dinner. The city of Paris said so.